Understanding and measuring iridescence (spectral banding) of anodized luminaire surfaces

Iridescence is a problem of increasing concern since the introduction of narrowband lamps and anodized luminaire surfaces. It appears as induced coloration of luminaire surfaces, much like rainbow patterns associated with thin oil or soap films on water. The causes of the effect are discussed, and an interim color measurement method based on standard CIE (1986) and ASTM (1987) practices for the measurement of color in terms of the human visual system is proposed. An analysis of the nature of the effect is provided so that the problem at hand can be better managed and understood